Microbial enzymes used in prodrug activation for cancer therapy: Insights and future perspectives

2020 ◽  
Vol 21 ◽  
Author(s):  
Rakhi Dhankhar ◽  
Anubhuti Kawatra ◽  
Aparajita Mohanty ◽  
Pooja Gulati
Keyword(s):  
Purine Nucleoside Phosphorylase ◽  
Cytosine Deaminase ◽  
Therapeutic Index ◽  
Enzyme Prodrug Therapy ◽  
Prodrug Activation ◽  
Microbial Enzymes ◽  
High Productivity ◽  
Delivery Vector ◽  
Exogenous Enzymes ◽  
Activation Therapy

Abstract:: Enzyme prodrug therapy has gained momentum in the recent years due to their ability to improve therapeutic index (benefits versus toxic side-effects) and efficacy of chemotherapy in cancer treatment. Inactive prodrugs used in this system are converted into active anti-cancerous drugs by enzymes, specifically within the tumor cells. This therapy involves three components namely prodrug, enzyme and gene delivery vector. Past reports have clearly indicated that the choice of enzyme used, is the major determinant for the success of this therapy. Generally, enzymes from non-human sources are employed to avoid off-target toxicity. Exogenous enzymes also give a better control to the clinician regarding the calibration of treatment by site-specific initiation. Amongst these exo-enzymes, microbial enzymes are preferred due to their high productivity, stability and ease of manipulation. The present review focuses on the commonly used microbial enzymes particularly cytosine deaminase, nitroreductase, carboxypeptidase, purine nucleoside phosphorylase in prodrug activation therapy. Various aspects viz. source of the enzymes, types of cancer targeted, mode of action and efficacy of the enzyme/prodrug system, efficient vectors used and recent research developments of each of these enzymes are comprehensively elaborated. Further, the results of the clinical trials and various strategies to improve their clinical applicability are also discussed.

scholarly journals Application of Gene-Directed Enzyme Prodrug Therapy in Cancer Treatment

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Cindy Yeoh Shin Ly ◽  
Anil Philip Kunnath
Keyword(s):  
Tumor Cells ◽  
Tumor Regression ◽  
Cytosine Deaminase ◽  
Therapeutic Index ◽  
Specific Gene ◽  
Enzyme Prodrug Therapy ◽  
E Coli ◽  
Carboxypeptidase G2 ◽  
High Concentrations ◽  
Simplex Virus

Gene-directed enzyme prodrug therapy (GDEPT) is an advanced cancer therapy that has potential use against localized and metastasized cancer. This strategy aims to improve the limitations of chemotherapy and existing cancer treatments by specific gene delivery, which allows the conversion of systemically administered nontoxic prodrugs to active chemotherapeutic drugs inside the target tumor cells, thereby resulting in a significant therapeutic index by introducing high concentrations of cytotoxic compounds to the tumor cells while limiting the systemic toxicity. The main attraction of GDEPT is by expanding the toxicity to adjacent non-expressing target cancer cells through local and distal bystander effects, leading to tumor regression. This review focused on the application of the six main GDEPT systems for treating cancer, including herpes simplex virus thymidine kinase (HSV-TK) with ganciclovir (GCV), cytosine deaminase (CD) from bacteria or yeast with 5-fluorocytosine (5-FC), E. coli nitroreductase (NfsB) with 5-(aziridin-1-yl)-2,4- initrobenzamide (CB1954), hepatic cytochrome P4l50 (CYP450) with cyclophosphamide (CPA), purine nucleoside phosphorylase (PNP) from E. coli with 6-methylpurine deoxyriboside (MEP), and bacterial carboxypeptidase G2 (CPG2) with 4-[(2-chloroethyl)(2-mesloxyethyl)amino] benzoyl-L-glutamic acid (CMDA). In each system, the mechanism of action, clinical trials for the past decades, limitations, and areas that need improvement are discussed.

Genetic Prodrug Activation Therapy for Breast Cancer: A Phase I Clinical Trial of erbB-2–Directed Suicide Gene Expression

1999 ◽  
Vol 17 (7) ◽  
pp. 2180-2180 ◽  
Author(s):  
Hardev S. Pandha ◽  
Lesley-Ann Martin ◽  
Anne Rigg ◽  
Helen C. Hurst ◽  
Gordon W.H. Stamp ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Gene Expression ◽  
Clinical Trial ◽  
Gene Therapy ◽  
Phase I ◽  
Cytosine Deaminase ◽  
Suicide Gene ◽  
Prodrug Activation ◽  
Targeted Gene Therapy ◽  
Activation Therapy

PURPOSE: This trial was designed to test the safety and efficacy of a tumor-specific genetic prodrug activation therapy targeted by use of the human erbB-2 gene promoter. The erbB-2 oncogene is overexpressed in approximately 20% of cases of breast cancer and is associated with poor prognosis. PATIENTS AND METHODS: Twelve breast cancer patients received transcriptionally targeted gene therapy in a phase I clinical trial using direct intratumoral injection of plasmid construct combined with systemic administration of prodrug. The genetic prodrug activation therapy is specifically targeted to erbB-2–overexpressing breast cancer cells by use of a therapeutic cassette that contains the Escherichia coli cytosine deaminase gene driven by the tumor-specific erbB-2 promoter, thus allowing activation of fluorocytosine to the active cytotoxic fluorouracil only within tumor cells that express the oncogene. RESULTS: The approach was shown to be safe and to result in targeted gene expression in up to 90% of cases. Using a number of different assays, we demonstrated that significant levels of expression of the suicide gene were specifically restricted to erbB-2–positive tumor cells, confirming the selectivity of the approach. CONCLUSION: The results of this study, the first targeted gene therapy for breast cancer and the first to use the cytosine deaminase system in human subjects, are encouraging for the development of genetic prodrug activation therapies that exploit the transcriptional profile of cancer cells.

scholarly journals The role of adenoviral vectors in genetic prodrug activation therapy in prostate cancer

2000 ◽  
Vol 3 (S1) ◽  
pp. S10-S10
Author(s):  
JD Eaton ◽  
IA Clarke ◽  
H Pandha ◽  
AG Dalgleish ◽  
RS Kirby
Keyword(s):  
Prostate Cancer ◽  
Adenoviral Vectors ◽  
Prodrug Activation ◽  
Activation Therapy

scholarly journals Cell-Penetrating Peptides as a Tool for the Cellular Uptake of a Genetically Modified Nitroreductase for use in Directed Enzyme Prodrug Therapy

2019 ◽  
Vol 10 (4) ◽  
pp. 45 ◽  
Author(s):  
Anderson ◽  
Hobbs ◽  
Gwenin ◽  
Ball ◽  
Bennie ◽  
...  
Keyword(s):  
Magnetic Nanoparticle ◽  
Genetically Modified ◽  
Cell Penetrating Peptides ◽  
Target Cells ◽  
Tumour Site ◽  
Enzyme Prodrug Therapy ◽  
Delivery Vector ◽  
Cell Penetrating ◽  
Subsequent Activation ◽  
Potential Use

Directed enzyme prodrug therapy (DEPT) involves the delivery of a prodrug-activating enzyme to a solid tumour site, followed by the subsequent activation of an administered prodrug. One of the most studied enzyme–prodrug combinations is the nitroreductase from Escherichia coli (NfnB) with the prodrug CB1954 [5-(aziridin-1-yl)-2,4-dinitro-benzamide]. One of the major issues faced by DEPT is the ability to successfully internalize the enzyme into the target cells. NfnB has previously been genetically modified to contain cysteine residues (NfnB-Cys) which bind to gold nanoparticles for a novel DEPT therapy called magnetic nanoparticle directed enzyme prodrug therapy (MNDEPT). One cellular internalisation method is the use of cell-penetrating peptides (CPPs), which aid cellular internalization of cargo. Here the cell-penetrating peptides: HR9 and Pep-1 were tested for their ability to conjugate with NfnB-Cys. The conjugates were further tested for their potential use in MNDEPT, as well as conjugating with the delivery vector intended for use in MNDEPT and tested for the vectors capability to penetrate into cells.

scholarly journals Imaging Expression of Cytosine Deaminase-Herpes Virus Thymidine Kinase Fusion Gene (CD/TK) Expression with [124I]FIAU and PET

2002 ◽  
Vol 1 (1) ◽  
pp. 153535002002000 ◽  
Author(s):  
Trevor Hackman ◽  
Michail Doubrovin ◽  
Julius Balatoni ◽  
Tatiana Beresten ◽  
Vladimir Ponomarev ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Thymidine Kinase ◽  
Enzyme Assay ◽  
Fusion Gene ◽  
Cytosine Deaminase ◽  
Prodrug Activation ◽  
Wide Range ◽  
Different Levels

Double prodrug activation gene therapy using the Escherichia coli cytosine deaminase (CD)herpes simplex virus type 1 thymidine kinase ( HSV1-tk) fusion gene ( CD/TK) with 5-fluorocytosine (5FC), ganciclovir (GCV), and radiotherapy is currently under evaluation for treatment of different tumors. We assessed the efficacy of noninvasive imaging with [124I]FIAU (2′-fluoro-2′-deoxy-1-β-d-arabinofuranosyl-5-iodo-uracil) and positron emission tomography (PET) for monitoring expression of the CD/TK fusion gene. Walker-256 tumor cells were transduced with a retroviral vector bearing the CD/TK gene (W256CD/TK cells). The activity of HSV1-TK and CD subunits of the CD/TK gene product was assessed in different single cell-derived clones of W256CD/TK cells using the FIAU radiotracer accumulation assay in cells and a CD enzyme assay in cell homogenates, respectively. A linear relationship was observed between the levels of CD and HSV1-tk subunit expression in corresponding clones in vitro over a wide range of CD/TK expression levels. Several clones of W256CD/TK cells with significantly different levels of CD/TK expression were selected and used to produce multiple subcutaneous tumors in rats. PET imaging of HSV1-TK subunit activity with [124I]FIAU was performed on these animals and demonstrated that different levels of CD/TK expression in subcutaneous W256CD/TK tumors can be imaged quantitatively. CD expression in subcutaneous tumor sample homogenates was measured using a CD enzyme assay. A comparison of CD and HSV1-TK subunit enzymatic activity of the CD/TK fusion protein in vivo showed a significant correlation. Knowing this relationship, the parametric images of CD subunit activity were generated. Imaging with [124I]FIAU and PET could provide pre- and posttreatment assessments of CD/TK-based double prodrug activation in clinical gene therapy trials.

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